Diffusers are known in the art. Diffusers are for widely scattering and/or spreading light, and are used in many different optical application including but not limited to wrist watches, projection systems, displays, computer screens, surgical equipment, optical communication systems, light sensors, fiber optic systems, microscope illumination systems, light guides, and so forth. Ultraviolet (UV) radiation can damage one or more of the aforesaid devices in which diffusers may be used. However, unfortunately, conventional diffusers do not block sufficient ultraviolet (UV) radiation which can lead to damage in one or more of the aforesaid optical devices.
Accordingly, it has been found that there exists a need in the art for a diffuser that can both function as a diffuser and block significant amounts of UV radiation.
Additionally, it has been found that certain organic UV coatings (with substantial organic UV blockers) are undesirable in that they are not heat resistant, and cannot withstand the high temperatures associated with thermal tempering of glass substrates. In particular, such organic UV blockers may undergo decomposition at high temperatures. Such organic UV coatings also suffer from a lack of mechanical durability, and thus are susceptible to yield loss. Moreover, in certain applications where a diffuser or organic coating thereon is subjected to high operating temperatures over prolonged times, organic based coatings tend to exhibit discoloration.
Thus, it will be appreciated that there also exists a need in the art for a high temperature resistant UV coating that is mechanically durable, and is capable of withstanding the high temperatures (e.g., from about 580 to 800 degrees C.) associated with thermal tempering of glass substrates.